نتایج جستجو برای: good yields
تعداد نتایج: 506625 فیلتر نتایج به سال:
Structurally different trimethyl silyl ethers are oxidized with Bu4/NIO4 in the presence of AlCl3 and BF3 as catalysts in CH3CN and CHCl3 under reflux conditions. The corresponding carbonyl compounds are isolated in good yields.
1, 8-Dioxo-octahydroxanthene derivatives have efficiently been synthesized from dimedone and aromatic aldehydes using [Fe(III)(salen)Cl] complex as an efficient and homogeneous catalyst in molten tetrabutyl ammonium bromide. This methodology offers several advantages, such as good yields, short reaction times, simple procedure, and mild conditions.
-A simple, efficient, and general method has been developed for the chemoselective acetalization of aldehydes with 1,3-propanediol, 1,2-ethanediol and trimethyl orthoformate in the presence of solid lithium perchlorate under solvent-free conditions. Both cyclic and acyclic acetals of aldehydes were obtained under environmentally benign conditions in good to excellent yields.
Some new 3-heterocyclyl-1,2,3-benzotriazin-4(3H)-ones (7a-f) were prepared in moderate to good yields by nitrosation of N-heterocyclyl-2- aminobenzanilides (6a-f). The latter were obtained by hydrazine hydrate-graphite reduction of corresponding N-heterocyclyl-2-nitrobenzanilides (5a-f)
In the present of methylimidazolium hydrogen sulfate, the synthesis of arylidene heterobicyclic pyrimidinones is studied by condensation of aromatic aldehyde, cyclopentanone, and urea or thiourea. Using solvent-free conditions, non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.
Nano-silica supported boron trifluoride (BF3.SiO2) is an efficient, reusable and eco-friendly catalyst for chemoselective thioacetalization of aldehydes and ketones. So, this catalyst was applied for transthioacetalization of acetals and acylals into their corresponding 1,3-dithiolanes or 1,3-dithianes in good to excellent yields. The reactions were carried out at room temperature under solven...
An efficient and expeditious catalyst-free procedure was developed for the one- pot synthesis of 1, 4-dihydropyridine derivatives via the three-component reaction of various aldehydes, ethyl acetoacetate, and ammonium acetate in PEG-400. The reaction was carried out at 110°С and the products were obtained in good to high yields.
Silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 by reaction with aromatic amines at room temperature in good to excellent yields. Imidate was prepared by treatment of equimolar quantities of triethyl orthoformate and diaminomaleonitrile in refluxing dioxane. All the compounds were characterized fully by ...
A new and improved protocol for the synthesis, in good to excellent yields, of acridine-1,8(2H,5H)-diones is described, involving a one-pot, three component reaction of dimedone, arylglyoxals, and ammonium acetate in water under microwave irradiation.
An efficient synthesis of isoquinoline-2,3-dicarboxylates is described via one-pot reactions of isoquinoline and alkyl bromids with dialkyl acetylenedicarboxylates in water at 70oC. The mild reaction conditions and high yields of the products exhibit the good synthetic advantage of these methods.
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